PROCELLARIIDAE 6 1 



a distinct fork occiivs in Oceanodroma. Sixteen rectrices are found 

 in Ossifraga, fourteen in Fulmarus, Priocella, and Daption, twelve 

 elsewhere. The small tongue is somewhat triangular, being rather 

 larger in Ossifraga and Prion ; the syrinx is tracheo-bronchial ; 

 and an after-shaft is present, though in some cases rudimentary. 



The soft, dense plumage shows various patterns of black, brown, 

 grey, and white ; the bill and feet may be black, brown, flesh- or 

 horn-tinted, yellow, orange, or parti -coloured, but in Prion and 

 Halohaena the latter are bluish. Light and dark phases are not 

 uncommon, as in Fulmarus and Ossifraga ; the sexes are invari- 

 ably similar ; and the nestlings, which long remain helpless, are 

 clad in thick down of a black, brown, grey, or white hue, through 

 which the feathers appear gradually. Some white Albatroses 

 have intermediate dusky stages of plumage, and do not gain the 

 adult coloration at once, as most of the Family seem to do. 



Diomedea exulans is one of the largest birds that fly, exceeding 

 a goose in size, while the smaller Petrels are hardly bigger than 

 Finches. The range of the Order is world-wide, though a majority 

 of species frequent the desolate tracts and islands of the southern 

 oceans ; but even Albatroses breed in the North Pacific. 



Though the members of this Family can hardly be called 

 gregarious, flocks of Shearwaters, Fulmars, and so forth are by 

 no means an uncommon sight from shipboard, and settlements are 

 formed in the breeding season, which is almost the only occasion 

 on which they voluntarily seek dry land. Albatroses, Fulmars, 

 the " Cape Pigeon " (Daption), and other allied forms are observed 

 most commonly in the daytime, whereas those that nest under 

 cover are to a great extent nocturnal during incubation, and 

 are generally seen or heard after dusk. While the whole group 

 is oceanic, there is a wide difference between the powerful 

 Albatros and its smaller and weaker relations in that respect, 

 the latter journeying but little from the immediate neighbour- 

 hood of their homes, and not accompanying ships for long dis- 

 tances in the same way as the former. In the larger species the 

 flight is strong and graceful,^ accompanied by circling, soaring, or 

 sailing movements, the feet being extended below the tail ; 

 Shearwaters skim the waves in a curious twisting fashion, and 

 the lesser Petrels flit with greater action of the wing close to the 



^ Here the late Professor Roy's article on " Fliglit " (A. Newtoii, Did. Birds, 

 lb93, \). 260) may be consulted. 



